Project description:Checkpoint inhibitors have revolutionized cancer treatment, but resistance remains a significant clinical challenge. Myeloid cells within the tumor microenvironment can modulate checkpoint resistance by either supporting or suppressing adaptive immune responses. Using an anti-PD-1 resistant mouse melanoma model, we show that targeting the myeloid compartment via CD40 activation and CSF1R blockade in combination with anti-PD-1 results in complete tumor regression in a majority of mice. This triple therapy combination is primarily CD40 agonist-driven in the first 24 hours post-therapy and shows a similar systemic cytokine profile in human patients as in mice. Functional single-cell cytokine secretion profiling of dendritic cells (DCs) using a novel microwell assay identified a CCL22+CCL5+ IL-12-secreting DC subset as important early-stage effectors of triple therapy. CD4+ and CD8+ T cells are both critical effectors of treatment, and systems analysis of single-cell RNA-sequencing data supports a role for DC-secreted IL-12 in priming T cell activation and recruitment. Finally, we show that treatment with a novel IL-12 mRNA therapeutic alone is sufficient to overcome PD-1 resistance and cause tumor regression. Overall, we conclude that combining myeloid-based innate immune activation and enhancement of adaptive immunity is a viable strategy to overcome anti-PD-1 resistance.
Project description:Checkpoint inhibitors have revolutionized cancer treatment, but resistance remains a significant clinical challenge. Myeloid cells within the tumor microenvironment can modulate checkpoint resistance by either supporting or suppressing adaptive immune responses. Using an anti-PD-1 resistant mouse melanoma model, we show that targeting the myeloid compartment via CD40 activation and CSF1R blockade in combination with anti-PD-1 results in complete tumor regression in a majority of mice. This triple therapy combination is primarily CD40 agonist-driven in the first 24 hours post-therapy and shows a similar systemic cytokine profile in human patients as in mice. Functional single-cell cytokine secretion profiling of dendritic cells (DCs) using a novel microwell assay identified a CCL22+CCL5+ IL-12-secreting DC subset as important early-stage effectors of triple therapy. CD4+ and CD8+ T cells are both critical effectors of treatment, and systems analysis of single-cell RNA-sequencing data supports a role for DC-secreted IL-12 in priming T cell activation and recruitment. Finally, we show that treatment with a novel IL-12 mRNA therapeutic alone is sufficient to overcome PD-1 resistance and cause tumor regression. Overall, we conclude that combining myeloid-based innate immune activation and enhancement of adaptive immunity is a viable strategy to overcome anti-PD-1 resistance.
Project description:Single cell RNA sequencing paired with single cell V(D)J sequenction of immune cells infiltrating orthotopic KPC2a tumors, spleen cells, and CD8 T cells enriched from spleen cells on day 14 posttumor. Cohorts received no treatment, agonistic anti-CD40, anti-PD-L1 or the combination of agonistic anti-CD40 + anti-PDL1. Treatments were initated on day 7 posttumor.
Project description:Pancreatic ductal adenocarcinoma (PDAC) has a poor survival rate and limited treatments. Agonistic CD40 antibodies are promising, but clinical trials have shown only modest efficacy and significant hepatotoxicity. We previously reported that IL-1 pathway blockade enhances CD40 agonist efficacy against melanoma by depleting polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs; CD11b+Ly6C+Ly6G+). Because PMN-MDSCs also cause liver toxicity, we investigated the impact of IL-1R1 blockade on the efficacy and toxicity of agonistic CD40 antibody therapy in PDAC. Agonistic CD40 antibody therapy induced immune activation and significantly prolonged survival in orthotopic PDAC-bearing mice. The combination of an agonistic CD40 antibody and IL-1R1 blockade upregulated multiple immune-related pathways and enhanced innate and adaptive responses. However, it did not further improve CD40 efficacy or reduce liver toxicity. The efficacy of the CD40 agonist was partially dependent on CD8⁺ T cells. Our findings underscore the complex role of IL-1 signaling in modulating immune responses in PDAC and caution against pursuing IL-1R1 blockade, either as monotherapy or combined with agonistic CD40 antibodies, in clinical trials for PDAC.
Project description:Therapeutic use of agonistic anti-CD40 antibodies is a potentially powerful approach for activating the immune response to eradicate tumors. However, the translation of this approach to clinical practice has been significantly restricted due to the severe dose-limiting toxicities observed in multiple clinical trials. Here, we demonstrate that conventional type-1 dendritic cells are essential for triggering antitumor immunity but not toxicity by CD40 agonists, while macrophages, platelets, and monocytes lead to the toxic events. Therefore, we designed bispecific antibodies that target CD40 activation preferentially to dendritic cells. These bispecific reagents demonstrate a superior safety profile compared to their parental CD40 monospecific antibody, while triggering potent anti-tumor activity. We suggest such cell-selective bispecific agonistic antibodies as a drug platform to bypass the dose-limiting toxicities of anti-CD40, and of additional types of agonistic antibodies used for cancer immunotherapy.